you seem not to be banned because of inconclusive results for sixtrack.

so , maybe try to reset the project in your boinc client , or detach and re attach it to see if there is an improvement.
But for the moment , there is no six track wu available.Look at the status project , so you have to wait for them.
And check your web preferences.
It's perhaps time for you to test another sub-project ? (for instance theory needs only little ram per work unit)(but you have to install virtualbox and its pack extension).